I tried a different enclosure with woofers firing out and port firing back and with my seat unbolted and out of the vehicle I managed to do 147.2 @ 68hz and 146.2 @ 68hz with seat down and in vehicle. I gained about 3 db by changing enclosures and raising 24hz in tone. All measuments done on term lab. Im extremely happy with the score but always tring to improve with my current equipment. What should be my next move to gain a few more decibles and still stay within usaci rules. Any sugestions on box tuning or equipment would be greatly appreciated. Sounds like your doin ok at 146+. I had 3 JL12W6 in a 4th order bandpass. The great thing about the bandpass is how efficient you can get them but at the same token you lose your frequency range the more efficient it gets. Mine was in an extra cab pickup with no rear seat and the box was pretty monsterous for 3 12's, 12+ cubic feet most of it in the ported chamber, the larger the ported chamber in comparison to the driver side the more efficient it is (to a point) so they take up alot of room if spl is what your going for. I was able to get 148+ out if it but had it tuned to low I think for great spl numbers that number was hit at 37hz. I love bandpass boxes but the downside is/or was in my case a bad case of trunkitice, windows down the thing pounded alot hard than up. Not sure if that helps you at all. FM